08/22/2025

On August 22, Spaceweather.com[1] reports a fast-moving Coronal Mass
Ejection, or CME, left the Sun on August 21.ÿ However, it is not Earth-directed, and is predicted to strike the planet Mars.

Solar activity has decreased back to low levels with a few weak
C-class flares observed from areas located in the northeast quadrant
of the solar disk. There are currently three sunspot regions on the
solar disk with the largest being Region AR4187. This region showed
some weak leader spot growth. The remaining two regions were quiet
and stable.
ÿ
Solar wind parameters reflected negative polarity coronal hole high
speed stream (CH HSS) influences. A disturbed solar wind environment
is likely to continue through August 22.

There is a slight chance for R1 (Minor) radio blackouts through
August 23 due to the anticipated return of old active regions.
Probabilities increase slightly to a chance for an isolated event,
most likely from the east limb, on August 24 as old active regions
return to view.

Active conditions are likely again on August 28 due to negative
polarity Coronal Hole High Speed Stream influences. Periods of G1 to
G2 (Minor-Moderate) storming are likely on September 5, with active
conditions likely on September 4 and 6, due to positive polarity
Coronal Hole High Speed Stream influences. The remainder of the
period is expected to be at quiet or quiet to unsettled levels.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere, August 21, 2025, by F. K. Janda, OK1HH:

"Higher solar activity in the first half of August was caused mainly
by two sunspot groups (out of a total of 11-13), whose magnetic
configuration allowed for the occurrence of moderately powerful
eruptions (class M). After their disappearance, the number of groups
dropped to three to five, while only energetically insignificant
eruptions sporadically occurred. Changes in the speed of the solar
wind and the concentration of particles in it had a significant
impact on the Earth's ionosphere. As usual, the source on the Sun
was the boundaries of coronal holes.

"After a brief calm in the geomagnetic field from August 13 to 15,
turbulent developments followed from August 19. At the beginning,
the speed of the solar wind rapidly increased from 350 to 650 km/s,
which was accompanied by a change in the polarity of the
longitudinal component of the interplanetary magnetic field Bz to
positive in a relatively long interval from 1130 to 1630 UT.
Therefore, the deterioration of shortwave propagation conditions was
only slight, while the MUF decline was delayed. We are now likely to
see a series of relatively calm days, probably until August 27.

Major disturbances are not expected to occur until around September
5, when the Earth will enter the same stream of solar particles as
it did around August 9."

The latest video from Dr. Tamitha Skov, WX6SWW, can be found on
YouTube at, https://www.youtube.com/watch?v=brxIxVgiH_A[2] .

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[3] and the ARRL Technical Information
Service web page at, http://arrl.org/propagation-of-rf-signals[4]. For
an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[5] . Information and
tutorials on propagation can be found at, http://k9la.us/[6] .

Also, check this:

https://bit.ly/3Rc8Njt[7]

"Understanding Solar Indices" from September 2002 QST.

The Predicted Planetary A Index for August 23 to 29 is 5, 5, 8, 8,
10, 12, and 8, with a mean of 8.ÿ Predicted Planetary K Index is 2,
2, 3, 3, 3, 4, and 3, with a mean of 2.9.ÿ 10.7 centimeter flux is
120, 125, 120, 120, 125, 125, and 130, with a mean of 123.6.

ÿ


[1] http://Spaceweather.com
[2] https://www.youtube.com/watch?v=brxIxVgiH_A
[3] http://www.arrl.org/propagation
[4] http://arrl.org/propagation-of-rf-signals
[5] http://arrl.org/the-sun-the-earth-the-ionosphere
[6] http://k9la.us/
[7] https://bit.ly/3Rc8Njt

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